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Biomedical subjects

J Kiss

Publications and source records attributed to J Kiss.

At least 55 records · Page 3Linked to original sources
PubMed1999

Formation and transposition of the covalently closed IS30 circle: the relation between tandem dimers and monomeric circles.

In the present study, we demonstrate that a circular IS30 element acts as an intermediate for simple insertion. Covalently closed IS and Tn circles constructed in vitro are suitable for integration into the host genome. Minicircle integration displays all the characteristics of transpositional fusion mediated by the (IS30 )2 dimer regarding target selection and target duplication. Evidence is provided for in vivo circularization of the element located either on plasmids or on the genome. It is shown that circle formation can occur through alternative pathways. One of them is excision of IS30 from a hot spot via joining the IRs. This reaction resembles the site-specific dimerization that leads to (IS30 )2 establishment. The other process is the dissolution of (IS30 )2 dimer, when the element is excised from an IR-IR joint. These pathways differ basically in the fate of the donor replicon: only dimer dissolution gives rise to resealed donor backbone. Analysis of minicircles and the rearranged donor replicons led us to propose a molecular model that can account for differences between the circle-generating processes. Our focus was to the dissolution of IR-IR joints located on the host genome, because these events promoted extensive genomic rearrangements and accompanied minicircle formation. The results present the possibility of host genome reorganization by IS30-like transposition.

DNA Transposable Elements↗
PubMed1999

Placental macrophage contact potentiates the complete replicative cycle of human cytomegalovirus in syncytiotrophoblast cells: role of interleukin-8 and transforming growth factor-beta1.

Although syncytiotrophoblast (ST) cells can be infected by human cytomegalovirus (HCMV), in vitro studies have indicated that ST cells do not support the complete viral reproductive cycle, or HCMV replication may occur in less than 3% of ST cells. The present study tested the possibility that placental macrophages might enhance activation of HCMV carried in ST cells and, further, that infected ST cells would be capable of transmitting virus to neighboring macrophages. For this purpose, we studied HCMV replication in ST cells grown alone or cocultured with uninfected placental macrophages. Our results demonstrated that HCMV gene expression in ST cells was markedly upregulated by coculture with macrophages, resulting in release of substantial amounts of infectious virus from HCMV-infected ST cells. After having become permissive for viral replication, ST cells delivered HCMV to the cocultured macrophages, as evidenced by detection of virus-specific antigens in these cells. The stimulatory effect of coculture on HCMV gene expression in ST cells was mediated by marked interleukin-8 (IL-8) and transforming growth factor-beta1 (TGF-beta1) release from macrophages, an effect caused by contact between the different placental cells. Our findings indicate an interactive role for the ST layer and placental macrophages in the dissemination of HCMV among placental tissue. Eventually, these interactions may contribute to the transmission of HCMV from mother to the fetus.

Antigens, Viral↗
PubMed1999

Role of interleukin-8 and transforming growth factor-beta1 in enhancement of human cytomegalovirus replication by human T cell leukemia-lymphoma virus type I in macrophages coinfected with both viruses.

Human cytomegalovirus (HCMV) is one of the most frequent opportunistic agents causing severe illness in chronic human T cell leukemia-lymphoma virus type I (HTLV-I) infection. Our previous studies have shown that coinfection of macrophages with HCMV and HTLV-I significantly enhances HCMV replication, resulting in release of infectious HCMV from dually infected cells. We found that double infection of macrophages with HCMV and HTLV-I induced a rapid production of substantial amounts of interleukin-8 (IL-8) and transforming growth factor-beta1 (TGF-beta1). Results of transfection studies demonstrated that the tax gene product of HTLV-I was able to induce secretion of IL-8 and TGF-beta1. In addition to its cytokine-inducing effect, the Tax protein could interact with HCMV synergistically to result in production of much higher levels of IL-8 and TGF-beta1 than expected on the basis of their separate activities. Treatment of dually infected macrophage cultures with neutralizing antibodies to IL-8 and TGF-beta1 led to a nearly 1000-fold decrease in release of infectious HCMV from coinfected cells. Similar results were obtained when anti-IL-8 and anti-TGF-beta1 treatments were combined in macrophage cultures transfected with the tax gene before HCMV infection. Our results suggest that the stimulatory effect of HTLV-I Tax protein on HCMV replication in coinfected macrophages is largely mediated by high levels of IL-8 and TGF-beta1 production.

Antibodies, Monoclonal↗
PubMed1999

The history and the future of teaching and training of laparoscopic surgery in Hungary.

INTRODUCTION: Laparoscopic biliary surgery was introduced in Hungary at the end of the 1990. A variety of experimental training and teaching courses had been performed in basic techniques and the human field, which was followed by laparoscopic biliary surgery and various advanced fields. AIMS OF THE STUDY: To review the history of teaching and training of laparoscopic surgery in Hungary in both the experimental and the human field, and to draw the consequences of this experience. MATERIAL AND METHODS: In a period of 6 years 704 qualified surgeons received a full hands--on hands experimental training in laparoscopic biliary surgery, laparoscopic advanced surgery, laparoscopic gynaecologic and laparoscopic urology surgery. DISCUSSION: The courses performed in the first and the second phase were of theoretical and practical components. The theoretical knowledge was based with emphasise to the new instruments and equipment, the indications, the new surgical technique. The practical knowledge gave every participant the full time to acquire this new type of surgery. At the end of the courses the successful participants received certificates to shift for training to the human field. Each institution needs to wrestle with issues concerning credentialling in advanced laparoscopic surgery. Like many technical skills, proficiency is maintained through repetition. A philosophy must be developed to determine whether each surgeon will perform this highly specialised type of surgery or whether it will be considered a general skill.

Animals↗
PubMed1999

Laparoscopic wedge resection of the gastric wall for gastric benign tumour. The collaboration of the laparoscopic surgeon and the endoscopist.

INTRODUCTION: By the introduction of the laparoscopy for the management of gastric pathology many techniques are applied by now. In these techniques the collaboration of the endoscopist and the laparoscopic surgeon is mandatory. AIMS OF THE STUDY: To emphasise the necessity of the collaboration of the endoscopist and the laparoscopic surgeon for the management of the gastric pathology using the double lifting and wedge resection technique. METHOD: A case of a female with 2 x 2.5 cm submucosal tumour is presented. The tumour was located in the antrum. After the onset of the general anaesthesia the gastroscope was introduced to locate the position of the tumour, the free edges of the tumour were elevated by a double lifting method and the tumour was resected by a laparoscopic linear stapler. The process of the proper resection was all through observed and directed by the view of the gastroscope. CONCLUSION: Correct wedge resection of the gastric wall can be safely performed, if the correct gastroscopic control is present. The collaboration of the endoscopist and the laparoscopic surgeon seems to be mandatory, thus avoiding the hazards arising from the use of tattooing.

Female↗
PubMed1999

The judgement of adhesion formation following laparoscopic and conventional cholecystectomy in an animal model.

INTRODUCTION: The development of postoperative adhesions remains an almost inevitable consequence of visceral and gynaecologic surgery, appearing in 50-95% of all patients. Although decreased adhesion formation is one of the accepted advantages of laparoscopic surgery, only a small number of prospective studies have been done to support this claim. AIMS OF THE STUDY: To evaluate the extent of postoperative adhesion formation after laparoscopic and open cholecystectomy. MATERIAL AND METHOD: 60 experimental laparoscopic cholecystectomies (LC) were performed by qualified surgeons in dogs with the aim to acquire the laparoscopic technique. To assess the relation between the complications during the operation (bleeding, injury to the liver substance or gallbladder perforation) and the formation of adhesions, the surviving animals were divided into 4 groups according to the complications occurred. The assessment of the results was made by second--look laparoscopy 4 weeks following LC using the adhesion index. As a control group open cholecystectomy was then performed in 5 dogs without intraoperative complications. RESULTS: No adhesion formation was observed in the groups where no intraoperative complications occurred. In all the cases where bleeding or injury to the liver bed occurred adhesion formation occurred. No adhesion formation was observed in case of gallbladder perforation. In all the animals of the control group adhesion formation was observed. CONCLUSION: It seems that LC has a reduced rate of adhesion formation when compared with the open technique. Complications such as bleeding or injury to the liver substance during LC can enhance adhesion formation. No adhesion formation can be mentioned in relation with gallbladder perforation when the laparoscopic technique is applied.

Adjuvants, Immunologic↗
PubMed1998

Metabotropic glutamate receptor in vasopressin, CRF and VIP hypothalamic neurones.

The excitatory amino acid glutamate, acting via ionotropic and metabotropic glutamate receptors, appears to play an important role in the control of neuroendocrine functions. The aim of the present investigations was to determine whether hypothalamic neurones which synthesize arginin-vasopressin (AVP), CRF and VIP express metabotropic glutamate receptor (mGluR). Double-label immunocytochemistry and the mirror technique were used. We found that AVP immunoreactive neurones of the paraventricular, supraoptic and suprachiasmatic nuclei contain mGluR1a, but the number of double-labelled neurones was different in the three cell groups. mGluR1a was present in a significant number of paraventricular CRF nerve cells, and in almost all VIP neurones of the SCHN. These results support the view that the excitatory transmitter glutamate may directly influence AVP, CRF and VIP neurones of the three hypothalamic cell groups.

Animals↗
PubMed1998

Endogenous vasopressin increases acute endotoxin shock-provoked gastrointestinal mucosal injury in the rat.

Administration of a low dose of endotoxin (from Escherichia coli, 3 mg kg(-1), i.v.), which does not affect vascular permeability or blood pressure over 1 h, leads to the release of endogenous vasopressin and damage to the mucosal microvasculature. Thus, endogenous vasopressin could be involved in septic shock. In the present study, we investigated the role of endogenous vasopressin in gastrointestinal mucosal injury induced by acute endotoxin shock, which was generated in rats by administering a high dose of E. coli endotoxin (50 mg kg(-1), i.v.). Tissues were removed 15 min after endotoxin. The vasopressin V1 receptor antagonist, d[CH2]5Tyr[Me]arginine-vasopressin (0.2-1 microg kg(-1), i.v.), was injected 10 min before endotoxin. Monastral blue (30 mg kg(-1), i.v.), which stains damaged vasculature, was injected 10 min before autopsy. Endotoxin reduced systemic arterial blood pressure (from 115+/-5 to 42+/-4 mmHg), generated macroscopic and microvascular injury, and elevated plasma vasopressin levels (from 3.4+/-0.2 to 178+/-16 pg ml(-1)). The vasopressin V1 receptor antagonist reduced this macroscopic injury, and in the vasopressin-deficient Brattleboro rat a similar reduction of gastrointestinal mucosal damage was found. Substantial decreases in endotoxin-induced microvascular damage were observed in each tissue, e.g., the gastric Monastral blue staining was reduced by 47+/-3% and 96+/-3% (P < 0.01) after vasopressin V1 receptor antagonist treatment and in Brattleboro rats, respectively. Vasopressin, acting through its V1 receptors, thus appears to be involved in acute endotoxin shock-provoked gastrointestinal injury.

Animals↗
PubMed1998

Reciprocal interactions between human cytomegalovirus and human T cell leukemia-lymphoma virus type I in monocyte-derived macrophages cultured in vitro.

Infection of macrophages with human cytomegalovirus (HCMV) has been shown to be nonlytic and exclusively cell associated. Human T cell leukemia-lymphoma virus type I (HTLV-I) is capable of establishing productive infection in macrophages. We studied the interactions between HCMV and HTLV-I in monocyte-derived macrophages cultured in vitro. We found that coinfection of macrophages with HCMV and HTLV-I significantly enhanced HCMV replication, resulting in release of infectious HCMV from dually infected cells. On the other hand, HCMV inhibited HTLV-I replication in macrophages coinfected with both viruses. Reciprocal interactions between HCMV and HTLV-I were mediated by their trans-acting proteins. Results of transfection studies demonstrated that the tax gene product of HTLV-I alone was capable of upregulating HCMV production. In a transient gene expression assay the immediate-early 2 (IE2) protein of HCMV alone could inhibit HTLV-I replication, whereas the IE1 protein, which had no effect by itself, produced a synergistic inhibitory effect together with the IE2 protein. Results from this study suggest that in vivo double infection of macrophages with HCMV and HTLV-I may contribute to the dissemination of HCMV infection in patients suffering from HTLV-I-associated T cell leukemia-lymphoma.

Antigens, Viral↗
PubMed1998

[Determination of the upper margin of superficial esophageal cancer by intraoperative endoscopic examination and toluidine blue staining].

Authors describe a new application of intraoperative endoscopic examination. At operation it is difficult to define the border of a superficial esophageal cancer. The female patient aged 69 years was operated on because of squamous cell cancer. During the operation endoscopic examination was done and the esophageal mucosa was stained with 1% toluidine blue solution. The squamous cancer stained blue. The upper border ot the tumour was determined so that the esophageal wall was palpated from the outside with a probe and the same time the manipulation was being watched on the monitor of the videoendoscope. Subtotal esophagectomy and lymphadenectomy were performed. Authors claim that by the intraoperative use of endoscopic staining the risk recurrence in an anastomosis may be diminished and leaving behind of multifocal carcinoma may be eliminated.

Aged↗
PubMed1998

Fibrous dysplasia associated with intramuscular myxoma (Mazabraud's syndrome): a long-term follow-up of three cases.

The association between of fibrous dysplasia and intramuscular myxomas is extremely rare. The authors summarize the characteristics of Mazabraud's syndrome, as well as its clinical course on the basis of 24 cases reported in the literature and 3 cases of their own. The syndrome is quite uniform, and mostly occurs in women. Usually the presentation of poliostotic fibrous dysplasia bilaterally in the lower limbs and pelvic bones is followed by the appearance of multifocal intramuscular myxomas in the adjacent muscles, mostly decades later. These hamartomas tend to recur locally or symmetrically in the ipsilateral muscle groups and may reach enormous size without treatment. Malignant transformation (osteosarcoma, fibrosarcoma) on the basis of fibrous dysplasia in Mazabraud's syndrome has been reported in the literature. In our cases, however, in spite of the many recurrences, and the enormous size of the tumours, no malignant transformation was noted in either the fibrous dysplasias or the intramuscular myxomas during the long follow-up time (31 years for fibrous dysplasia and 16 years for myxomas). Early wide surgical excision and a careful long-term follow-up for the often very late recurrences of the myxomas is suggested in Mazabraud's syndrome.

Adolescent↗
PubMed1998

The role of esophagectomy in the management of esophageal perforations.

BACKGROUND: Despite the many advancements made in thoracic surgery, the management of patients with esophageal perforation remains problematic and controversial. METHODS: Between 1985 and 1995, 27 esophagectomies were performed for perforation of the thoracic esophagus. A retrospective review of the records of these patients was carried out, and a scoring scale developed by Elebute and Stoner to grade the severity of sepsis was applied. RESULTS: Among the 27 patients undergoing esophagectomy for a perforation, the interval between rupture and esophagectomy was less than 24 hours in only 11 patients (40.7%). Postoperative surgical complications occurred in 4 patients (14.8%) and nonsurgical complications, in 7 (25.9%). The hospital mortality rate was 3.7% (1/27). In 14 patients, primary reconstruction was performed in the bed of the excised esophagus. There were no anastomotic leaks in this subgroup. This suggests that an anastomosis between viable, well-vascularized tissues is more important for successful healing than avoidance of some degree of contamination of the adjacent mediastinum. On follow-up, which averages 41 months, 73% of patients (16/22) have neither symptoms nor complaints. CONCLUSIONS: Esophageal resection definitively eliminates the source of intrathoracic sepsis, the perforation, and the affected esophagus. Reconstruction carried out in one stage does not increase operative morbidity. Esophageal resection and reconstruction is a valid approach even in cases of spontaneous perforation in which the diagnosis is markedly delayed.

Adult↗
PubMed1998

Induction of nitric oxide synthase in vivo and cell injury in rat duodenal epithelium by a water soluble extract of Helicobacter pylori.

1. Helicobacter pylori (Hp) infection, which involves the gastric antrum and duodenal mucosa, may be involved in peptic ulceration by stimulating the local release of cytoxic or pro-inflammatory factors. 2. Nitric oxide (NO) is known to be cytotoxic at high concentration. The aim of the present study was therefore to investigate the ability of a water soluble extract of Hp to induce NO synthase in duodenal mucosa and epithelial cells following its administration in vivo in rats and determine its association with cell damage. 3. Administration of Hp water extract (4 ml kg(-1)) led to the expression of the calcium-independent inducible nitric oxide synthase (iNOS) after 4 h in the duodenum, determined as [14C]-arginine conversion to citrulline. 4. This iNOS activity was not reduced by pretreatment with anti-neutrophil serum (0.4 ml kg(-1), i.p., 3 h before challenge). However, dexamethasone pretreatment (1 mg kg(-1), i.v., 2 h before the extract), or administration of the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 5 mg kg(-1), i.v., 2.5 h after the extract) reduced this activity. 5. Furthermore, iNOS was expressed in duodenal isolated epithelial cells 4 h after the i.v. challenge with the extract, at a time when the cellular viability was also reduced, as assessed by trypan blue exclusion. 6. Dexamethasone pretreatment, administration of L-NAME, or pretreatment with polymyxin B (1 mg kg(-1), i.v.) which binds endotoxin, reduced both the iNOS activity and epithelial cell damage. 7. The induction of NO synthase by the Hp extract thus results in duodenal epithelial cell injury and such actions could play a role in pathogenesis of peptic ulcer disease.

Animals↗
PubMed1998

Target specificity of insertion element IS30.

The Escherichia coli resident mobile element IS30 has pronounced target specificity. Upon transposition, the element frequently inserts exactly into the same position of a preferred target sequence. Insertion sites in phages, plasmids and in the genome of E. coli are characterized by an exceptionally long palindromic consensus sequence that provides strong specificity for IS30 insertions, despite a relatively high level of degeneracy. This 24-bp-long region alone determines the attractiveness of the target DNA and the exact position of IS30 insertion. The divergence of a target site from the consensus and the occurrence of 'non-permitted' bases in certain positions influence the target activity. Differences in attractiveness are emphasized if two targets are present in the same replicon, as was demonstrated by quantitative analysis. In a system of competitive targets, the oligonucleotide sequence representing the consensus of genomic IS30 insertion sites proved to be the most efficient target. Having compared the known insertion sites, we suppose that IS30-like target specificity, which may represent an alternative strategy in target selection among mobile elements, is characteristic of the insertion sequences IS3, IS6 and IS21, too.

Binding Sites↗
PubMed1998

Clinical significance and application of anorectal physiology.

During the last decade, interest in anorectal disorders has increased continuously. This review presents the results of Hungarian authors' contributions to a better understanding of anorectal physiology over the last 10 years. It has been demonstrated that the surgical technique of pelvic floor reconstruction can be refined and surgical complication rates reduced through the analysis of anal basal pressure components and exploration of internal anal sphincter function. Objective assessment of anal continence (distinguishing continent from incontinent patients) is a consistent problem in clinical practice. The balloon-retaining test, a special application of manometry, facilitates evaluation of anorectal function in incontinent patients. Constipation is an extremely common symptom. Surgical treatment of these ailments should not be regarded as a first-choice therapy. Disordered defecation due to anismus can be identified by defecometry, and can eventually be treated by biofeedback training. The data presented here demonstrate the enormous impact of sophisticated diagnostic techniques on the therapeutic options in treatment of anorectal diseases.

Adult↗